Over the last few decades, the dimensions of electronic devices have been continuously scaled down, leading to exponential gains in computational power and reduced production costs. The down-scaling has been enabled inter alia by advances in patterning techniques based on for instance optical lithography.
To further improve the performance of electronic devices, potential materials for device fabrication are being investigated. One type of material of great interest is transition metal dichalcogenide (TMDC) materials. A TMDC material may be formed by a stack of monolayers of the TMDC material. The monolayers typically present a strong in-plane bonding (i.e. within a basal plane) but weak interlayer attraction due to van der Waals interactions.
A hetero-stack of two different TMDC materials could form the basis for devices presenting band-to-band-tunneling, a high Ion/Ioff ratio and lower power consumption. For instance, a tunneling field effect transistor (TFET) including a vertical hetero-stack of TMDC materials shows promise as a replacement for the conventional metal-oxide-semiconductor field-effect transistors (MOSFETS).
Although techniques for forming proof-of-concept TMDC hetero-stack devices have been presented, challenges remain to be overcome before large-scale production of such devices becomes feasible.